1. Field of the Invention
The present invention relates to a device for conducting hot-rolled strip through an inductor of an induction heating device arranged between two adjacent roll stands and, in particular, in a finishing mill behind a strip-casting or thin-slab casting plant.
2. Description of the Prior Art
In the finish rolling of hot strips, it is frequently necessary to adjust the temperature of the rolling stock to rolling temperature before the stock is introduced into the roll stand. If the reheating of the rolling stock is effected by induction heating in the break-down mill, it is carried out with large cross sections of the rolling stock and slow rolling speeds. It is also customary to bring the rolling stock to rolling temperature by gas-heated furnaces. The reheating in the finishing mill is effected at higher speeds and requires special measures, since small cross sections must be heated.
Recently, strip-casting methods and thin-slab casting plants have become increasingly important. In this connection, a continuously cast pre-strip is fed directly for further shaping. An endless rolling with the advantage of rolling at a uniform heat is desired. However, problems arise in connection with the guidance of the rolling stock both at start-up and during the rolling. Problems also arise in connection with the adjustments of the rolling speeds within the train of rolls.
European Patent Application 01 62 361, discloses a device for adjusting the tension of the strip in a hot-rolled strip mill, which serves to determine the changing tensions of the strip and to accordingly adjust the speeds of roll stands of the hot-strip rolling mill so as to keep the variations in the tensile forces low.
In order to improve the control of the temperature in the strip, German patent 38 40 812 provides devices for inductive heating, which counteract the cooling of the strip during the rolling, between two adjacent roll stands of a finishing mill, behind a thin-slab casting plant. This is of importance, in particular, when rolling so-called thin slabs since, as a result of the small cast cross sections, the thermal energy stored in the material is frequently not sufficient to maintain the necessary final rolling temperatures. If strip thicknesses of less than 2 mm are to be obtained, a heating of the rolling stock in the region of the finishing-mill is unavoidable. Heating upon the rolling of cross sections from strip-casting plants becomes even more necessary when several stands are required for rolling.
Induction heating devices are well adapted to provide the necessary thermal energy, since they are capable of bringing about uniform temperature changes within a very short time. A uniform temperature is the prerequisite for strip of good quality, and the uniform temperature is to be assured in the strip by the inductor.
For the uniform heating in the inductor, however, a constant distance between induction coil and rolling stock is also a prerequisite. However, this can be obtained only with an undisturbed as possible position of the strip within the inductor, in which connection the top and bottom sides of the strip should be at an equal distance from the coils. In the extreme case, disturbance and fluttering of the strip in the induction space can otherwise lead to non-uniform temperatures or arcing between coil and strip, by which the surface of the strip is damaged.